Preparation and electromagnetic shielding properties of PET/rGO/SWCNT composite fabric

Graphene oxide(GO)with excellent dispersion ability can assist the dispersion of single-walled carbon nanotube(SWCNT)and promote the formation of uniform and stable GO/SWCNT coating liquid.The highly conductive polyethylene terephthalate/reduced graphene oxide/SWCNT(PET/rGO/SWCNT)electromagnetic shielding composite fabric was successfully prepared by anchoring rGO/SWCNT on PET fabric via dip-coating piror to low-temperature thermal reduction.The results showed that the carboxyl groups and hydroxyl groups formed of hydrophilic-treated PET were conducive to the formation of hydrogen bonds with that of GO,which enhanced the interaction between PET fabric and GO/SWCNT coating;the loading of GO/SWCNT increased with the number of dip-coating,the unit area loading of rGO/SWCNT in the final composite fabric was 2.7 mg/cm^(2) after 10 dip-coating cycles and thermal reduction;the PET/rGO/SWCNT composite fabric had a continuous and dense conductive network,with a conductivity of up to 41.6 S/m and the average electromagnetic interference shielding effectiveness in X-band was 22 dB;the flexible PET/rGO/SWCNT composite fabric was not only easy to process,but also exhibited excellent conductivity and shielding efficiency,showing great potential in the application of electromagnetic shielding fabrics.

Study on Shielding Effectiveness of Fabric for Electromagnetic Wave with Different Inlaid Distances of Metal Fibres

The electremagnetic radicalization has become more serious. The shielding effectiveness of polyester fabrics with different inlaid distance of parallel metal fibres to electromagnetic wave was studied in this paper on special instrument made by ourselves. The results of test show that the fabric with different inlaid distances of metal fibres and the testing angle between electric field plane and parallel metal fibres of have obvious effect on the shielding effectiveness of electromagnetic wave.

3D-structured carbon nanotube fibers as ultra-robust fabrics for adaptive electromagnetic shielding

Wireless communication technology is indispensable in our daily lives,but it also results in serious electromagnetic radiation pollution.Hence,developing smart electromagnetic interference shielding materials with adjustable electromagnetic wave(EMW)responses holds significant promise for future electromagnetic shielding devices.In this study,we propose an electromagnetic shielding switch(ESS)characterized by tunable electromagnetic shielding performance achieved by fabricating a three-dimensional(3D)carbon nanotube-based spacer fabric(CNT-SF)and modifying CNT-SF with chemical vapor deposition(CCNT-SF).The CCNT-SF displays direction-dependent electrical conductivity by manipulating the warp and weft density,measuring 128 S/m transversely and 447 S/m vertically.This characteristic allows the CCNT-SF to transmit or shield EMW by adjusting the angle of EMW incidence through fabric rotation,resulting in anisotropic electromagnetic shielding performance(33 dB transversely and 87 dB vertically).This feature enables switchable shielding with an on/off ratio of 2.64.Furthermore,the unique 3D structure confers excellent mechanical properties on the fabric,with compressive strength reaching 120 kPa.As a flexible,lightweight,and mechanically robust ESS,the CCNT-SF holds promising prospects for mitigating the challenges of increasingly severe and intricate electromagnetic environments.

Flexible MXene/sodium alginate composite fabric with high structural stability and oxidation resistance for electromagnetic interference shielding

Wearable electromagnetic interference(EMI)shielding fabrics with excellent electromagnetic shielding performance,oxidation resistance,and structural stability are highly demanded for the rapid development of electronic devices and wireless communication.MXenes are metallic conductive materials with exceptional EMI shielding properties,but they are prone to oxidation in air and have poor structural stability and durability on fabric substrates.Herein,we present a one-step assembly method to fabricate fabrics coated with MXenes and polymeric sodium alginate(SA)composite(MXene-SA).SA protects MXenes from oxidation and forms a stable interlayer structure by bonding to MXenes.The MXene-SA coated fabrics are breathable and flexible,and have a low sheet resistance of 2.12±0.08Ω/sq and a high EMI shielding performance of 37.05 dB at X-band,which is comparable to the best 42.31 dB.Moreover,the MXene-SA coated fabrics exhibit high structural stability and oxidation resistance under various conditions of sonication disintegration,mechanical abuse,chemical corrosion,and humidity,compared to pure MXenes coated fabrics.We believe that the wearable and high-performance MXene-SA fabrics have great potential for the next generation of ultra-portable and wearable EMI shielding products.

The Effects of Dyeing and Finishing Pretreatment Process to the Sliver Fiber Shielding Fabric and the Reasons

Through the silver fiber and cotton mixed silver fiber shielding fabric,not only soft and comfortable,it can wear personal,but also has excellent anti electromagnetic shielding effect. Fabric in dyeing and finishing process,may cause some damage on the silver fiber,influence the shielding performance of shielding fabric. Therefore,in this paper,through the experimental and analysis,find dyeing and finishing process may affect silver fiber shielding fabric and the reasons.

Superhydrophobic self-extinguishing cotton fabrics for electromagnetic interference shielding and human motion detection

Multifunctional intelligent fire-safe cotton fabric promises next-generation fire-fighting uniform and sen-sor applications.However,cotton fabrics’hygroscopicity and intrinsic flammability significantly impede their potential applications in industries.Herein,we report a superhydrophobic fireproof cotton fabric(PEI-APP-PEI-MXene)generated via sequential layer-by-layer deposition of polyethyleneimine(PEI),am-monium polyphosphate(APP),and titanium carbide(MXene),followed by hydrophobic treatment with silicone elastomer.Compared to untreated cotton,the treated cotton fabric with 10 polymolecular layers exhibits∼43%and∼42%reductions in the peak heat release rate and total heat release,respectively,a desired UL-94 V-0 rating,and a high limiting oxygen index(LOI)value of 39.5 vol.%.In addition to that,the treated fabrics displayed improved electromagnetic interference(EMI)shielding and motion-sensing abilities.The presented work provides a facile and effective surface modification approach to generate multifunctional cotton fabrics with promising practical applications.

A stretchable fabric as strain sensor integrating electromagnetic shielding and electrochemical energy storage

Multifunctional intelligent fabric plays an integral role in health management,human–machine interaction,wireless energy storage and conversion,and many other artificial intelligence fields.Herein,we demonstrate a newly developed MXene/polyaniline(PANI)multifunctional fabric integrated with strain sensing,electrochemical energy storage,and electromagnetic shielding properties.The multifunctional fabric-based strain sensor possesses a real-time signal response at a sizeable tensile strain of 100%with a minute strain of 0.5%,maintaining a stable and consistent signal response even after 3000 stretch–release cycles.In addition,the multifunctional fabric exhibits excellent electromagnetic shielding capabilities,achieving a total shielding effectiveness value of up to 43 dB,and in the meantime shows attractive electrochemical energy storage performance as an electrode in a supercapacitor,offering a maximum specific capacity and energy density of 522.5 mF·cm^(−2)and 18.16μWh·cm^(−2),respectively.Such a multifunctional intelligent fabric offers versatile opportunities to develop smart clothes for various artificial intelligent applications.

Robust double-layered ANF/MXene-PEDOT:PSS Janus films with excellent multi-source driven heating and electromagnetic interference shielding properties

The strategy of incorporating polymers into MXene-based functional materials has been widely used to improve their mechanical properties,however with inevitable sacrifice of their electrical conductivity and electromagnetic interference(EMI)shielding performance.This study demonstrates a facile yet efficient layering structure design to prepare the highly robust and conductive double-layer Janus films comprised of independent aramid nanofiber(ANF)and Ti3C2Tx MXene/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)layers.The ANF layer serves to provide good mechanical stability,whilst the MXene/PEDOT:PSS layer ensures excellent electrical conductivity.Doping PEDOT:PSS into the MXene layer enhances the interfacial bonding strength between the MXene and ANF layers and improves the hydrophobicity and water/oxidation resistance of MXene layer.The resultant ANF/MXene-PEDOT:PSS Janus film with a conductive layer thickness of 4.4μm was shown to display low sheet resistance(2.18Ω/sq),good EMI shielding effectiveness(EMI SE of 48.1 dB),high mechanical strength(155.9 MPa),and overall toughness(19.4 MJ/m^(3)).Moreover,the excellent electrical conductivity and light absorption capacity of the MXene-PEDOT:PSS conductive layer mean that these Janus films display multi-source driven heating functions,producing excellent Joule heating(382℃ at 4 V)and photothermal conversion(59.6℃ at 100 mW/m^(2))properties.

Biomass-based aligned carbon networks with double-layer construction for tunable electromagnetic shielding with ultra-low reflectivity

Nowadays,carbon frameworks derived from natural biomaterials have attracted extensive attention for electromagnetic interference(EMI)shielding due to their renewability and affordability.However,it is critical and challenging to achieve effective regulation of shielding effectiveness(SE)as well as weaken the strong EM reflection of highly conductive biomass-based carbon materials.Herein,commercial cotton pads with oriented structure were selected as carbonaceous precursor to fabricate aligned carbon networks by pyrolysis,and the EMI SE of the samples with increased temperature of 800-1000℃ can be accurately controlled in the effective range of~21.7-29.1,~27.7-37.1 and~32.7-43.3 d B with high reflection coefficient of>0.8 by changing the cross-angle between the electric-field direction of incident EM waves and the fiber-orientation direction due to the occurrence of opposite internal electric field.Moreover,the further construction of Salisbury absorber-liked double-layer structure could result in an ultralow reflection coefficient of only~0.06 but enhanced SE variation range up to~38.7-49.3 d B during the adjustment of cross-angle,possibly due to the destructive interference of EM waves in the double-layer carbon networks.This work would provide a simple and effective way for constructing high-performance biomass carbon materials with adjustable EMI shielding and ultra-low reflectivity.

MXene在电磁屏蔽织物领域应用最新研究进展

MXene作为一种新型二维纳米材料,具有导电性高、比表面积大、耐热性好和密度低等优点,是一种优良的导电填料,其在电磁屏蔽织物领域的应用也越来越多。文中简述MXene材料的合成过程及应用;介绍MXene的电磁屏蔽机理及其复合纤维制备方法,包括涂层法、双辊法、静电纺丝法、湿法纺丝法等,并对比各方法的优缺点;总结MXene在电磁屏蔽织物应用领域的最新研究进展。最后展望MXene在电磁屏蔽织物应用领域的发展方向,为新一代电磁屏蔽性能优异、稳定性强、力学性能强、舒适性好的MXene复合纤维的研究提供新思路。

氨纶预牵伸倍数对棉/氨纶/不锈钢丝包覆纱性能的影响

针对面向个体防护装备的涂层类电磁屏蔽材料存在无弹性、保形性差、不耐洗涤、舒适性差等不足,基于空心锭包缠纺纱机,以氨纶为纱芯、不锈钢丝和棉股线为第一和第二外包覆层,纺制兼具优良弹性和电磁屏蔽功效的棉/氨纶/不锈钢丝包覆纱。探究氨纶预牵伸倍数对包覆纱强伸性能、回弹性能的影响,利用模糊综合评判法优化工艺参数,实现纬向弹性电磁屏蔽机织物的设计构筑。结果表明:氨纶预牵伸倍数对包覆纱性能影响显著。在设定范围内,氨纶预牵伸倍数为2.5时,包覆纱综合质量较优,且在拉伸应变下具有稳健的导电特征。此外,基于包覆纱制备的纬向弹性机织物具有优良的可拉伸性,电磁屏蔽效能与织物放置方向、拉伸应变程度等密切相关。相关研究结果可为开发电磁屏蔽耐久性好、高度可拉伸且服用性能优良的电磁屏蔽织物提供新思路。

MoO_(2)-NC/聚偏氟乙烯复合材料的制备及其电磁屏蔽性能

现代电子信息技术的飞速发展给人类生活带来巨大便利的同时也产生了严重的电磁干扰问题,不仅会影响电子设备的正常使用,而且还会危害人类健康。鉴于此,亟需开发高性能电磁屏蔽材料来解决电磁辐射污染。本文结合简单的水热法、原位化学氧化聚合和高温碳化工艺成功制备出一维异质纳米填料MoO_(2)-NC,并将其填充于柔性聚偏氟乙烯(PVDF)基体中,通过简单的溶液混合和热压技术制备出一系列MoO_(2)-NC不同质量分数下的MoO_(2)-NC/PVDF复合材料,研究了复合材料整体的电磁屏蔽性能。结果表明,经高温处理后,将前驱体聚吡咯(PPy)热解为碳材料,同时通过碳热还原法将MoO3还原成MoO_(2),使得纳米填料的电导率获得大幅提升,MoO_(2)-NC的电导率在20 MPa下最高能达到133.67 S/cm,比煅烧前的样品增加了28倍。当MoO_(2)-NC的质量分数为40%时,复合材料具有优异的电磁屏蔽性能,这一复合物的总屏蔽效能在X波段范围内最高能达到32.2 dB,比商用标准(20 dB)高出60%,由此表明MoO_(2)-NC具有作为高效电磁屏蔽功能填料的应用潜力。

无表面活性剂微乳液制备导电聚苯胺及对有机材料的包覆性能

在水、乙醇、二氯甲烷构成的无表面活性剂微乳液中成功合成了纳米级聚苯胺。通过扫描电镜探究了以水包油(O/W)和油包水(W/O)两种状态的微乳液为模板制备的聚苯胺的微观形貌,发现在无表面活性剂微乳液中合成的聚苯胺纳米粉具有颗粒细且均匀、产物易分离的优点。通过红外光谱和X射线衍射图谱验证了聚苯胺在微乳液中的合成。在对不同底物的包覆试验中,发现具有亲水性的变色硅胶可以被W/O微乳液合成的纤维状的聚苯胺包裹,而在O/W微乳液中仅在缝隙处生成了棒状的聚苯胺。具有疏水性的涤纶织物在W/O微乳液中聚合聚苯胺后表面生成了聚苯胺颗粒但未能形成连续镀层,在O/W微乳液中形成致密镀层并具有一定的导电性能。通过控制氧化剂配比和反应时间探究聚苯胺-涤纶织物的最佳电导率,当苯胺与氧化剂物质的量比为1∶1.3,反应时间为4 h时,聚苯胺达到最佳电导率5.66×10^(-2)S/cm。

碳纳米管/水性聚氨酯导电涂层棉织物的制备及性能

以碳纳米管和水性聚氨酯为主要组分合成导电油墨,制备导电涂层棉织物。研究了碳纳米管质量分数对油墨导电性能的影响,探讨了涂层整理次数对导电涂层棉织物微观形貌和宏观性能的影响规律,并测试了导电涂层棉织物的耐水洗/耐摩擦性能和热稳定性能。结果表明:涂层棉织物具有良好的导电和电磁屏蔽性能;当碳纳米管质量分数为20%,涂层整理4次制备的导电涂层棉织物电导率达到16.9 S/m,在X波段的平均屏蔽效能为27.3 dB,且表现出优良的拉伸性能、透气性和功能稳定性。

结构参数对不锈钢织物透光与电磁屏蔽的影响

为实现不锈钢织物高透明与强电磁屏蔽性能相兼容的目标,文章采用数值计算与理论分析相结合的方法,在分析不锈钢织物主要结构参数(线径与线距)对其透光与电磁屏蔽性能影响的基础上,引入TOPSIS评价方法,探讨了线径与线距对不锈钢织物光学与电磁学综合性能的影响。结果表明,由于电磁衍射的存在,结构参数对透光与电磁屏蔽性能的影响呈现非线性规律。其中,不锈钢织物的线距变化对总体性能的影响最为密切。当线径在0.02~0.05 mm且线距在0.4~1.0 mm时,不锈钢织物在90%高透光率的前提下,可达到至少30 dB的屏蔽效能,为高透光电磁屏蔽材料的结构设计提供了理论指导。

织物单双层结构设计对电磁屏蔽性能的影响

为了研究不同织物结构对织物电磁屏蔽性能的影响,采用导电镀银纤维与不锈钢长丝以及绝缘锦纶长丝为原料,织造了具有电磁屏蔽性能的单双层织物。在织物结构中,以锦纶长丝为经纱,导电纤维作为纬纱,按照一定的比例设计并织造了系列单层和双层织物,并对织物的基本性能及电磁屏蔽性能进行了测试分析。结果表明:双层织物中纬纱为1根锦纶纤维和2根镀银纤维交替织造织物(B1)的电磁屏蔽性能达到最佳,为42.4 dB;纬纱为1根锦纶纤维和2根不锈钢纤维交替织造织物(B4)的电磁屏蔽效果为40.5 dB;电磁屏蔽性能随着导电纤维含量的增加显著提高;在导电纤维含量相同时,镀银纤维织物的电磁屏蔽效果比不锈钢纤维的电磁屏蔽性能好;双层织物的电磁屏蔽性能优于单层织物。

基于玻璃纤维织物的固-固相变树脂复合材料制备及电磁屏蔽性能

具备灵活热响应的电磁干扰(EMI)屏蔽复合材料是电磁防护、建筑工程、电子兼容等领域的理想候选材料之一。为制得该类EMI屏蔽复合材料,首先将异氰酸丙基三乙氧基硅烷(IPTS)与聚乙二醇(PEG)反应,获得具有高活性硅醇基团可自交联的柔韧固-固相变树脂(SPCR)基体,随后,通过SPCR封装被银纳米线(AgNWs)修饰的玻璃纤维织物(GFF)制备得到AgNWs/GFF/SPCR复合材料。测试了SPCR的结构和热稳定性,研究了AgNWs/GFF层数对复合材料电磁屏蔽性能的影响,最后测试了复合材料的热响应性能。结果表明,SPCR在保留原始PEG相变特性的同时具有优异的形状稳定能力,从而避免被泄漏。4层AgNWs/GFF组成的复合材料在2.8 mm厚度下的EMI屏蔽效能(SE)约为73 dB。电磁波吸收效能(SEA)随着EMI SE的增加呈现出递增的趋势,而电磁波反射效能(SER)在6~18 dB范围内波动。同时,反射系数(R)远大于吸收系数(A),AgNWs/GFF/SPCR复合材料表现出明显的反射主导屏蔽机制。此外,AgNWs/GFF/SPCR复合材料在升温和降温过程均表现出明显的温度滞后现象。因此,AgNWs/GFF/SPCR复合材料在电磁辐射防护和设备热管理方面具有广阔的前景。

聚吡咯/石墨烯/锦纶织物的制备及电磁屏蔽性能

将锦纶织物反复浸渍氧化石墨烯(GO)水分散液,取出烘干后还原制备rGO/锦纶织物;再将其浸渍于吡咯(Py)的酸性水溶液中,引发聚合反应制备PPy/rGO/锦纶织物,优化了rGO/锦纶和PPy/rGO/锦纶织物的制备工艺,即:rGO/锦纶织物浸渍于7.5 g/L的Py分散液中,pH=2,15 min后在0℃条件下滴加5 mL质量浓度为3.0 g/L的APS溶液,振荡器转速为150 r/min。制备的PPy/rGO/锦纶织物的方块电阻为(97±8)Ω/,电磁屏蔽效果为42.7 dB。

含银功能纤维及织物应用进展

简要介绍了纤维表面镀银、母粒纺丝、静电纺丝以及浸渍法等制备方法的基本原理、加工工艺特点以及对纤维及织物功能性作用的优劣等;围绕抗菌性、导电性和电磁屏蔽性等应用场景,综述了含银纤维及织物的国内外的制备及应用进展,详细分析了含银纤维及织物的最新制备机理、作用机制及其在抗菌性、导电性和电磁屏蔽性等方面的构效关系;最后,展望了含银纤维及织物在生物医用、可穿戴电子设备、通信、军工等领域的潜在应用价值。

玻璃纤维/碳纤维织物基复合材料的电磁屏蔽性能

为增强碳纤维织物复合材料对电磁波的阻抗匹配性,减少二次反射,采用玻璃纤维调控碳纤维织物组织结构,并将其与水性聚氨酯复合,设计并制备了5种玻璃纤维/碳纤维(G/C)织物复合材料。借助超景深显微镜、矢量网络分析仪、模拟日光氙灯光源系统、红外热成像仪对G/C织物复合材料的形貌结构、电磁屏蔽性能、介电性能以及光热转化性能进行表征和分析。结果表明:在12.1 GHz下,纬纱采用2根玻璃纤维和单根碳纤维交替排列织造的G/C织物复合材料的屏蔽效能高达38.7 dB;G/C织物复合材料的组织结构变化可有效调控多种介电极化弛豫机制;G/C织物复合材料表面温度在模拟日光氙灯光源照射下响应速度快,其中玻璃纤维和碳纤维单根交替排列的G/C织物复合材料在2 kW/m^(2)光照强度下照射300 s时,其表面温度可达71.8℃。